Method of treating manganese steel.



WINFIELD S. POTTER,

OF NEW YORK, N. Y.

METHOD OF TREATING MANGANESE STEEL.

No Drawing.

Specification of Letters Patent. Application filed May 2, 1910. SerialNo. 558,845.

Patented Nov. 8, 1010.

To all whom it may concern:

Be it known that I, VVINFIELD S. POTTER, a citizen of the United States,and a resident of New York, borough of Manhattan, in the county of NewYork and State of-New York, have made and invented certain new anduseful Improvements in Methods of T reating Manganese Steel, of whichthe following is a specification.

My invention relates to a method of treating metals, and moreparticularly to the treatment of manganese steel previously strengthenedand toughened, e. 9., by having been rapidly cooled from a hightemperature, the object of the invention'being to so treat the metalthat it may be bent, t'orged, or otherwise worked into finished shapeswithout injury to the steel, either by straining it during the formingoperation, or by destroying, reducing, or impairing its strength ortoughness.

Manganese steel when rapidly cooled from high temperatures, as forinstance, by quenching it in water, has imparted thereto the desirablequalities of great strength and toughness, but these qualities aregreatly impaired when the metal is reheated to certain temperatures, andentirely destroyed it the metal be reheated to those temperatures atwhich other metals are ordinarily worked into finished shapes or forms,the steel becoming weak and brittle. After numerous experiments,however, I have found that if the metal be reheated to temperatures notabove 425 C., which is a sufiicient temperature to permit of it beingworked, it is in nowise injured.

From my various experiments I have also discovered that if plates, bars,or other shapes of manganese steel be bent,'twisted, or otherwisedistorted, when reheated to temperatures below 225 (1., the metal willbe injured and no longer exhibit the Same desirable qualities ofstrength and toughness. Tests made upon specimens cut from a rolled bar,reheated to temperatures between 250 (1. and 550 (1., and subsequentlyWorked, show but slight deterioration, and specimens reheated totemperatures between 350 (1. and 125 (1. substantially the same'resultsas tests made on the original bar.

In carrying my methodinto practice, the rolled rail, bar, plate, orother shape having been rapidly cooled from a high temperature, and themetal thereby strengthened or toughened, is reheated throughout totemperatures between 225 (1., and 550 C., preferably to a temperaturebetween 350 (1. and 425 (1., as between these limits I have found thereis no likelihood of injury to the steel. The metal is thenwrought,pressed, bent, or otherwise worked or formed into the finished shapedesired, and subsequently either cooled in the air, or more rapidlycooled in water.

\Vhile the temperatures which I have above mentioned are the mostdesirable at which the metal should be worked in order .to avoid anyliability of injury thereto from the reheating thereof, or by strainingit in the process of working, yet it ispossible to work the metal at aslightly higher temperature, for example 550 (1., providing it be notretained at such temperature for too long a time; in such instance, itis very desirable, in factnecessary, that themetal be rapidly worked andsubsequently rapidly cooled to a temperature preferably below 100 (1. Inany event, however, it is not desirable to reheat the metal to atemperature much above (300 (1., as I have found that by so doing, thecrystallization of the metal is so changed or altered as to render itweak and brittle.

What I claim is:

1. The method of treating manganese steel previously strengthened andtoughened, which consists in reheating such metal to a temperature notabove 550 (1., then working the metal into it's finished form, andfinally cooling it.

2. The method hereinbefore described of treating manganese steelpreviously strengthened and toughened, consisting in reheating suchmetal to a temperature between 225 C. and 550 (1., then forming themetal into its finished shape, and finally cooling it.

3. The method of treating manganese steel previously strengthened andtoughened, consisting in reheating such metal to a temperatureapproximating 400 (1., then forming the metal into its finished shape,and finally cooling it.

Signed at New York, borough of Manhattan, in the county of New York, andState of New York, this 27th day of April, A. D. 1910. I L

WINFIELD S. POTTER.

Witnesses:

OAKLEY W. CooKn, WILLIAM CoNovER.

hereinbefore described

